The present invention relates generally to the field of arc welding, and more particularly to the field of tungsten inert gas (TIG) arc welding torches.
Arc welding is a welding process in which an electric current is used to produce localized melting in a work piece. There are many different types of arc welding processes. One example of an arc welding process is TIG welding (also known as gas tungsten arc welding, GTAW, or HELIARC). TIG welding is a type of arc welding process in which an electric arc is maintained between a welding implement, such as a hand-held welding torch, and a metal work piece. Typically, the welding implement includes a cylindrical electrode coupled to a torch head. The arc is produced by electricity that flows between the electrode and the work piece. Typically, the electrode is comprised of tungsten. The electricity for the arc welding process is provided by a power source coupled to the torch head of the welding implement by a power cable.
In TIG welding, a gas is directed toward the work piece to form a shield around the point of contact of the arc on the work piece. The gas shield prevents impurities from entering the weld puddle while it is in a molten state. A gas lens may be used to establish desired flow characteristics in the shield gas. For example, the gas lens may be used to produce a more uniform flow of gas across the width of the gas flow. Alternatively, the gas lens may be used to produce a slower flow of gas. Typically, a gas lens comprises at least one screen disposed in the flow path of the gas. However, a porous disc may be used, rather than a screen.
Typically, gas lenses that have used a porous disc have simply replaced the screen with the porous disc. The porous disc is wedged into a gas lens housing to secure the porous disc to the gas lens housing. By wedging the porous disc into the gas lens housing, friction is produced between the porous disc and the gas lens housing that secures the porous disc within the gas lens housing. However, wedging the porous disc inside the gas lens housing makes removal of the porous disc from the housing difficult. In some cases, a tool may be required to pry the porous disc loose from within the gas lens housing.
Therefore, a need exists for a technique to enable a porous disc to be secured within a welding torch without having to use friction to secure the porous disc within the housing. More specifically, a need exists for a technique to enable a porous disc to be secured within a welding torch such that the porous disc is fully accessible so that the porous disc does not have to be pried loose from a housing.